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Malaria Journal Mar 2019Plasmodium knowlesi is a zoonotic malaria parasite normally residing in long-tailed and pig-tailed macaques (Macaca fascicularis and Macaca nemestrina, respectively)... (Review)
Review
Plasmodium knowlesi is a zoonotic malaria parasite normally residing in long-tailed and pig-tailed macaques (Macaca fascicularis and Macaca nemestrina, respectively) found throughout Southeast Asia. Recently, knowlesi malaria has become the predominant malaria affecting humans in Malaysian Borneo, being responsible for approximately 70% of reported cases. Largely as a result of anthropogenic land use changes in Borneo, vectors which transmit the parasite, along with macaque hosts, are both now frequently found in disturbed forest habitats, or at the forest fringes, thus having more frequent contact with humans. Having access to human hosts provides the parasite with the opportunity to further its adaption to the human immune system. The ecological drivers of the transmission and spread of P. knowlesi are operating over many different spatial (and, therefore, temporal) scales, from the molecular to the continental. Strategies to prevent and manage zoonoses, such as P. knowlesi malaria require interdisciplinary research exploring the impact of land use change and biodiversity loss on the evolving relationship between parasite, reservoir hosts, vectors, and humans over multiple spatial scales.
Topics: Animals; Borneo; Disease Transmission, Infectious; Ecosystem; Humans; Macaca fascicularis; Macaca nemestrina; Malaria; Plasmodium knowlesi; Primate Diseases; Zoonoses
PubMed: 30849978
DOI: 10.1186/s12936-019-2693-2 -
Journal of Microbiology, Immunology,... Oct 2019Plasmodium knowlesi is now regarded as the fifth malaria parasite causing human malaria as it is widely distributed in South-East Asian countries especially east... (Review)
Review
Plasmodium knowlesi is now regarded as the fifth malaria parasite causing human malaria as it is widely distributed in South-East Asian countries especially east Malaysia where two Malaysian states namely Sabah and Sarawak are situated. In 2004, Polymerase Chain Reaction (PCR) was applied for diagnosing knowlesi malaria in the Kapit Division of Sarawak, Malaysia, so that human P. knowlesi infections could be detected correctly while blood film microscopy diagnosed incorrectly as Plasmodium malariae. This parasite is transmitted from simian hosts to humans via Anopheles vectors. Indonesia is the another country in South East Asia where knowlesi malaria is moderately prevalent. In the last decade, Sarawak and Sabah, the two states of east Malaysia became the target of P. knowlesi research due to prevalence of cases with occasional fatal infections. The host species of P. knowlesi are three macaque species namely Macaca fascicularis, Macaca nemestrina and Macaca leonina while the vector species are the Leucosphyrus Complex and the Dirus Complex of the Leucophyrus Group of Anopheles mosquitoes. Rapid diagnostic tests (RDT) are non-existent for knowlesi malaria although timely treatment is necessary for preventing complications, fatality and drug resistance. Development of RDT is essential in dealing with P. knowlesi infections in poor rural healthcare services. Genetic studies of the parasite on possibility of human-to-human transmission of P. knowlesi were recommended for further studies.
Topics: Animals; Anopheles; Asia, Southeastern; Diagnostic Tests, Routine; Humans; Insect Vectors; Macaca fascicularis; Malaria; Malaysia; Monkey Diseases; Plasmodium knowlesi; Polymerase Chain Reaction; Prevalence; Rural Health
PubMed: 31320238
DOI: 10.1016/j.jmii.2019.05.012 -
The American Journal of Tropical... Mar 2021Zoonotic knowlesi malaria has replaced human malaria as the most prevalent malaria disease in Malaysia. The persistence of knowlesi malaria in high-risk transmission...
Zoonotic knowlesi malaria has replaced human malaria as the most prevalent malaria disease in Malaysia. The persistence of knowlesi malaria in high-risk transmission areas or hotspots can be discouraging to existing malaria elimination efforts. In this study, retrospective data of laboratory-confirmed knowlesi malaria cases were obtained from the Sarawak Health Department to investigate the spatiotemporal patterns and clustering of knowlesi malaria in the state of Sarawak from 2008 to 2017. Purely spatial, purely temporal, and spatiotemporal analyses were performed using SaTScan software to define clustering of knowlesi malaria incidence. Purely spatial and spatiotemporal analyses indicated most likely clusters of knowlesi malaria in the northern region of Sarawak, along the Sarawak-Kalimantan border, and the inner central region of Sarawak between 2008 and 2017. Temporal cluster was detected between September 2016 and December 2017. This study provides evidence of the existence of statistically significant Plasmodium knowlesi malaria clusters in Sarawak, Malaysia. The analysis approach applied in this study showed potential in establishing surveillance and risk management system for knowlesi malaria control as Malaysia approaches human malaria elimination.
Topics: Humans; Incidence; Malaria; Malaysia; Plasmodium knowlesi; Retrospective Studies; Spatio-Temporal Analysis
PubMed: 33755585
DOI: 10.4269/ajtmh.20-1304 -
Malaria Journal Nov 2022Indonesia is progressing towards malaria elimination. To achieve this goal, intervention measures must be addressed to cover all Plasmodium species. Comprehensive...
BACKGROUND
Indonesia is progressing towards malaria elimination. To achieve this goal, intervention measures must be addressed to cover all Plasmodium species. Comprehensive control measures and surveillance programmes must be intensified. This study aims to determine the prevalence of microscopic and submicroscopic malaria in Langkat district, North Sumatera Province, Indonesia.
METHODS
A cross-sectional survey was conducted in six villages in Langkat district, North Sumatera Province in June 2019. Data were recorded using a standardized questionnaire. Finger pricked blood samples were obtained for malaria examination using rapid diagnostic test, thick and thin blood smears, and polymerase chain reaction.
RESULTS
A total of 342 individuals were included in the study. Of them, one (0.3%) had a microscopic Plasmodium malariae infection, no positive RDT examination, and three (0.9%) were positive for P. malariae (n = 1) and Plasmodium knowlesi (n = 2). The distribution of bed net ownership was owned by 40% of the study participants. The participants had a house within a radius of 100-500 m from the forest (86.3%) and had the housing material of cement floor (56.1%), a tin roof (82.2%), wooden wall (35.7%), bamboo wall (28.1%), and brick wall (21.6%).
CONCLUSION
Malaria incidence has substantially decreased in Langkat, North Sumatera, Indonesia. However, submicroscopic infection remains in the population and may contribute to further transmission. Surveillance should include the detection of microscopic undetected parasites, to enable the achievement of malaria elimination.
Topics: Humans; Plasmodium knowlesi; Plasmodium malariae; Cross-Sectional Studies; Indonesia; Malaria; Plasmodium falciparum
PubMed: 36333701
DOI: 10.1186/s12936-022-04335-y -
PLoS Neglected Tropical Diseases Dec 2020Plasmodium knowlesi, a simian malaria parasite, has been in the limelight since a large focus of human P. knowlesi infection was reported from Sarawak (Malaysian Borneo)... (Review)
Review
Plasmodium knowlesi, a simian malaria parasite, has been in the limelight since a large focus of human P. knowlesi infection was reported from Sarawak (Malaysian Borneo) in 2004. Although this infection is transmitted across Southeast Asia, the largest number of cases has been reported from Malaysia. The increasing number of knowlesi malaria cases has been attributed to the use of molecular tools for detection, but environmental changes including deforestation likely play a major role by increasing human exposure to vector mosquitoes, which coexist with the macaque host. In addition, with the reduction in human malaria transmission in Southeast Asia, it is possible that human populations are at a greater risk of P. knowlesi infection due to diminishing cross-species immunity. Furthermore, the possibility of increasing exposure of humans to other simian Plasmodium parasites such as Plasmodium cynomolgi and Plasmodium inui should not be ignored. We here review the current status of these parasites in humans, macaques, and mosquitoes to support necessary reorientation of malaria control and elimination in the affected areas.
Topics: Animals; Asia, Southeastern; Humans; Macaca; Malaria; Monkey Diseases; Mosquito Vectors; Plasmodium knowlesi
PubMed: 33382697
DOI: 10.1371/journal.pntd.0008900 -
Tropical Medicine & International... Aug 2022To characterise the state-wide epidemiology of indigenous knowlesi malaria in Sarawak from 2011 to 2019.
OBJECTIVES
To characterise the state-wide epidemiology of indigenous knowlesi malaria in Sarawak from 2011 to 2019.
METHODS
Longitudinal retrospective study was conducted based on Sarawak knowlesi malaria surveillance data recorded from 2011-2019. Only indigenous cases were included and information extracted for analysis comprised age, sex, occupation, ethnicity, case severity, hospital admission and parasite density.
RESULTS
Over the 9 years, 8473 indigenous knowlesi malaria cases were recorded. Age group 40-49 years, males, plantation workers and Iban communities recorded the highest percentage of cases in each demographic variable. Most of the cases were uncomplicated (n = 7292; 86.1%) and 89.6% (n = 7589) of the total cases were reported with ≤20 000 parasites/μl of blood. Age group and ethnic group are associated with the severity of knowlesi malaria in Sarawak. Multivariable logistic regression indicated that the age group 60+ years had the highest odds of developing severe knowlesi malaria compared with other age groups (AOR 2.48; 95% CI 1.22, 5.02; p = 0.012). Bidayuh patients were more likely to develop severe knowlesi malaria than Ibans, the largest ethnic group among knowlesi malaria patients (AOR 1.97; 95% CI 1.31, 2.97; p = 0.001).
CONCLUSIONS
Identification of risk groups is important for the implementation of prevention programs and treatments targeting at specific group to combat knowlesi malaria effectively.
Topics: Adult; Humans; Longitudinal Studies; Malaria; Malaysia; Male; Middle Aged; Plasmodium knowlesi; Retrospective Studies
PubMed: 35716113
DOI: 10.1111/tmi.13788 -
Scientific Reports May 2021Degradation of the endothelial glycocalyx is associated with mortality in adult falciparum malaria. However, its role in the pathogenesis of non-falciparum malaria is... (Clinical Trial)
Clinical Trial Observational Study
Degradation of the endothelial glycocalyx is associated with mortality in adult falciparum malaria. However, its role in the pathogenesis of non-falciparum malaria is unknown. In Malaysian patients with knowlesi (n = 200) and vivax (n = 61) malaria, and in healthy controls (n = 50), we measured glycocalyx breakdown products plasma syndecan-1 and urinary glycosaminoglycans, and evaluated correlations with biomarkers of disease severity. Urinary glycosaminoglycans were increased in patients with knowlesi and vivax malaria compared to healthy controls, and in knowlesi malaria were highest in those with severe disease. In knowlesi malaria, plasma syndecan-1 was also highest in those with severe disease, and correlated with markers of endothelial activation (angiopoietin-2, osteoprotegerin, ICAM-1), asymmetric dimethylarginine (ADMA) and impaired microvascular reactivity. Syndecan-1 also correlated with endothelial activation (ICAM-1, angiopoietin-2) and ADMA in vivax malaria. In knowlesi malaria increased syndecan-1 was associated with acute kidney injury, after controlling for age and parasitemia. In knowlesi malaria, the difference in median syndecan-1 between severe and non-severe disease was more marked in females than males. Endothelial glycocalyx degradation is increased in knowlesi and vivax malaria, and associated with disease severity and acute kidney injury in knowlesi malaria. Agents that inhibit glycocalyx breakdown may represent adjunctive therapeutics for severe non-falciparum malaria.
Topics: Acute Kidney Injury; Adolescent; Adult; Aged; Aged, 80 and over; Biomarkers; Endothelium, Vascular; Female; Glycocalyx; Humans; Malaria, Vivax; Male; Middle Aged; Plasmodium knowlesi; Plasmodium vivax; Prospective Studies; Severity of Illness Index
PubMed: 33963210
DOI: 10.1038/s41598-021-88962-6 -
International Journal of Infectious... May 2014Since the initial discovery of Plasmodium knowlesi in Malaysia, cases have been reported from several neighbouring countries. Tourism has also resulted in an increasing... (Review)
Review
OBJECTIVES
Since the initial discovery of Plasmodium knowlesi in Malaysia, cases have been reported from several neighbouring countries. Tourism has also resulted in an increasing number of cases diagnosed in Europe, America, and Oceania. In this review we focus on the risk of the travel-associated acquisition of P. knowlesi malaria.
METHODS
A search of the literature in PubMed was carried out to identify articles and literature on the distribution of P. knowlesi infections in Southeast Asia and details of its acquisition and importation by travellers to other continents. The cut-off date for the search was December 1, 2013. Search words used were: "Plasmodium knowlesi", "Plasmodium knowlesi infections", "Plasmodium knowlesi travellers", "Plasmodium knowlesi prevalence", "Plasmodium knowlesi host", "Plasmodium knowlesi vector" "Plasmodium knowlesi RDT", and "Plasmodium knowlesi Malaysia". Traveller numbers to Malaysia were obtained from the Tourism Malaysia website.
RESULTS
A total of 103 articles were found. Using a selection of these and others identified from the reference lists of the papers, we based our review on a total of 66 articles.
RESULTS
P. knowlesi malaria appears to be the most common malaria species in Malaysian Borneo and is also widely distributed on the Malaysian mainland. Furthermore, locally transmitted cases of P. knowlesi malaria have been reported in Thailand, the Philippines, Vietnam, Singapore, Myanmar, Indonesian Borneo, and Cambodia. Two cases have been reported from non-endemic countries in Asia (Japan and Taiwan) in people with a history of travel to Malaysia and the Philippines. Twelve cases were imported to their home countries by travellers from other continents: two from the USA, two from the Netherlands, two from Germany, and one each from Spain, France, Sweden, Finland, Australia, and New Zealand. In most cases, the infection was associated with a trip to or near forested areas. The symptoms were fever (n=12), headache (n=6), chills (n=6), nausea (n=4), myalgia (n=3), back pain (n=3), abdominal problems (n=1), anorexia (n=2), fatigue (n=2), malaise (n=1), arthralgia (n=1), sore throat (n=1) vomiting (n=2), and jaundice (n=1). All patients were treated successfully with currently available antimalaria treatments. The identification of the pathogen by microscopy can be problematic due to the morphological similarity of P. knowlesi to Plasmodium malariae.
CONCLUSION
P. knowlesi appears to be a threat not only to the local population in Malaysia, but also to the estimated 25 million annual tourists and occupational travellers to Malaysia, especially those who visit rural, forested areas of the country. The P. knowlesi risk is not limited to Malaysia, and travellers from Southeast Asia presenting with possible malaria should be considered for a diagnostic work-up that includes P. knowlesi.
Topics: Adult; Animals; Antimalarials; Asia, Southeastern; Child; Diagnosis, Differential; Female; Humans; Macaca fascicularis; Malaria; Male; Plasmodium knowlesi; Plasmodium malariae; Travel
PubMed: 24631521
DOI: 10.1016/j.ijid.2013.12.016 -
International Journal of Environmental... Mar 2022is a non-human parasite that causes zoonotic disease in humans. This systematic review aims to highlight and summarize studies describing human behaviors and activities... (Review)
Review
OBJECTIVES
is a non-human parasite that causes zoonotic disease in humans. This systematic review aims to highlight and summarize studies describing human behaviors and activities that expose humans to mosquito bites. English entries in PubMed, Web of Science, and Science Direct from 2010 to 2020 were systematically perused, and the results were synthesized. Methodological quality was assessed using the Joanna Briggs Institute quality appraisal checklists.
SETTING
Studies that described malaria preventive measures were included. Laboratory, in vivo, in vitro, and animal studies were excluded.
PRIMARY AND SECONDARY OUTCOME MEASURES
The main outcome of the review was findings from studies describing the behavior that exposed a person or a group to infection.
RESULTS
Twelve eligible studies were of good or medium quality. Attitude, disease misconceptions, perceived threat of disease, lack of motivation, and supernatural or traditional beliefs causing individuals to seek treatment from traditional healers influenced the exposure of individuals or communities to malaria. Other factors were forestry activities (2.48, 1.45-4.23,95% CI, = 0.0010) and sleeping outdoors (3.611, 1.48-8.85, 95% CI, = 0.0049).
CONCLUSIONS
Future studies must consider the importance of human behavior and community perspective on the infection to provide novel information to improve the current zoonotic malaria programs. Policymakers should concentrate on understanding human behavior and activities that expose individuals or communities to mosquito bites, in order to better design socially feasible interventions.
Topics: Animals; Humans; Insect Bites and Stings; Malaria; Motivation; Plasmodium knowlesi; Zoonoses
PubMed: 35329359
DOI: 10.3390/ijerph19063675 -
Genes Jun 2023Although Malaysia is considered free of human malaria, there has been a growing number of cases. This alarming trend highlighted the need for our understanding of this...
Although Malaysia is considered free of human malaria, there has been a growing number of cases. This alarming trend highlighted the need for our understanding of this parasite and its associated vectors, especially considering the role of genetic diversity in the adaptation and evolution among vectors in endemic areas, which is currently a significant knowledge gap in their fundamental biology. Thus, this study aimed to investigate the genetic diversity of , , , and -the vectors for malaria in Malaysia. Based on cytochrome c oxidase 1 () and internal transcribed spacer 2 () markers, the genealogic networks of showed a separation of the haplotypes between Peninsular Malaysia and Malaysia Borneo, forming two distinct clusters. Additionally, the genetic distances between these clusters were high (2.3-5.2% for ) and (2.3-4.7% for ), indicating the likely presence of two distinct species or cryptic species within . In contrast, no distinct clusters were observed in , , or , implying a lack of pronounced genetic differentiation among their populations. It is worth noting that there were varying levels of polymorphism observed across the different subpopulations, highlighting some levels of genetic variation within these mosquito species. Nevertheless, further analyses revealed that all four species have undergone demographic expansion, suggesting population growth and potential range expansion for these vectors in this region.
Topics: Humans; Animals; Malaria; Anopheles; Plasmodium knowlesi; Malaysia; Mosquito Vectors; Demography
PubMed: 37510274
DOI: 10.3390/genes14071369